ttrss/classes/feeds.php

<?php
require_once "colors.php";

class Feeds extends Handler_Protected {
	const NEVER_GROUP_FEEDS = [ -6, 0 ];
	const NEVER_GROUP_BY_DATE = [ -2, -1, -3 ];

	 private $params;

	 private $viewfeed_timestamp;
	 private $viewfeed_timestamp_last;

    function csrf_ignore($method) {
		$csrf_ignored = array("index");

		return array_search($method, $csrf_ignored) !== false;
	}

	private function _format_headlines_list($feed, $method, $view_mode, $limit, $cat_view,
					$offset, $override_order = false, $include_children = false, $check_first_id = false,
					$skip_first_id_check = false, $order_by = false) {

		$disable_cache = false;

		$this->_mark_timestamp("init");

		$reply = [];
		$rgba_cache = [];
		$topmost_article_ids = [];

		if (!$offset) $offset = 0;
		if ($method == "undefined") $method = "";

		$method_split = explode(":", $method);

		if ($method == "ForceUpdate" && $feed > 0 && is_numeric($feed)) {
            $sth = $this->pdo->prepare("UPDATE ttrss_feeds
                            SET last_updated = '1970-01-01', last_update_started = '1970-01-01'
                            WHERE id = ?");
            $sth->execute([$feed]);
		}

		if ($method_split[0] == "MarkAllReadGR")  {
			$this->_catchup($method_split[1], false);
		}

		// FIXME: might break tag display?

		if (is_numeric($feed) && $feed > 0 && !$cat_view) {
			$sth = $this->pdo->prepare("SELECT id FROM ttrss_feeds WHERE id = ? LIMIT 1");
			$sth->execute([$feed]);

			if (!$sth->fetch()) {
				$reply['content'] = "<div align='center'>".__('Feed not found.')."</div>";
			}
		}

		$search = $_REQUEST["query"] ?? "";
		$search_language = $_REQUEST["search_language"] ?? ""; // PGSQL only

		if ($search) {
			$disable_cache = true;
		}

		$qfh_ret = [];

		if (!$cat_view && is_numeric($feed) && $feed < PLUGIN_FEED_BASE_INDEX && $feed > LABEL_BASE_INDEX) {
			$handler = PluginHost::getInstance()->get_feed_handler(
				PluginHost::feed_to_pfeed_id($feed));

			if ($handler) {
				$options = array(
					"limit" => $limit,
					"view_mode" => $view_mode,
					"cat_view" => $cat_view,
					"search" => $search,
					"override_order" => $override_order,
					"offset" => $offset,
					"owner_uid" => $_SESSION["uid"],
					"filter" => false,
					"since_id" => 0,
					"include_children" => $include_children,
					"order_by" => $order_by);

				$qfh_ret = $handler->get_headlines(PluginHost::feed_to_pfeed_id($feed),
					$options);
			}

		} else {

			$params = array(
				"feed" => $feed,
				"limit" => $limit,
				"view_mode" => $view_mode,
				"cat_view" => $cat_view,
				"search" => $search,
				"search_language" => $search_language,
				"override_order" => $override_order,
				"offset" => $offset,
				"include_children" => $include_children,
				"check_first_id" => $check_first_id,
				"skip_first_id_check" => $skip_first_id_check,
                "order_by" => $order_by
			);

			$qfh_ret = $this->_get_headlines($params);
		}

		$this->_mark_timestamp("db query");

		$vfeed_group_enabled = get_pref("VFEED_GROUP_BY_FEED") &&
			!(in_array($feed, self::NEVER_GROUP_FEEDS) && !$cat_view);

		$result = $qfh_ret[0]; // this could be either a PDO query result or a -1 if first id changed
		$feed_title = $qfh_ret[1];
		$feed_site_url = $qfh_ret[2];
		$last_error = $qfh_ret[3];
		$last_updated = strpos($qfh_ret[4], '1970-') === false ?
			TimeHelper::make_local_datetime($qfh_ret[4], false) : __("Never");
		$highlight_words = $qfh_ret[5];
		$reply['first_id'] = $qfh_ret[6];
		$reply['is_vfeed'] = $qfh_ret[7];
		$query_error_override = $qfh_ret[8];

		$reply['search_query'] = [$search, $search_language];
		$reply['vfeed_group_enabled'] = $vfeed_group_enabled;

		$plugin_menu_items = "";
		PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_HEADLINE_TOOLBAR_SELECT_MENU_ITEM,
			function ($result) use (&$plugin_menu_items) {
				$plugin_menu_items .= $result;
			},
			$feed, $cat_view);

		$plugin_buttons = "";
		PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_HEADLINE_TOOLBAR_BUTTON,
			function ($result) use (&$plugin_buttons) {
				$plugin_buttons .= $result;
			},
			$feed, $cat_view);

		$reply['toolbar'] = [
			'site_url' => $feed_site_url,
			'title' => strip_tags($feed_title),
			'error' => $last_error,
			'last_updated' => $last_updated,
			'plugin_menu_items' => $plugin_menu_items,
			'plugin_buttons' => $plugin_buttons,
		];

		$reply['content'] = [];

		if ($offset == 0)
			PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_HEADLINES_BEFORE,
					function ($result) use (&$reply) {
						$reply['content'] .= $result;
					},
					$feed, $cat_view, $qfh_ret);

		$this->_mark_timestamp("object header");

		$headlines_count = 0;

		if ($result instanceof PDOStatement) {
			while ($line = $result->fetch(PDO::FETCH_ASSOC)) {
				$this->_mark_timestamp("article start: " . $line["id"] . " " . $line["title"]);

				++$headlines_count;

				if (!get_pref('SHOW_CONTENT_PREVIEW')) {
					$line["content_preview"] = "";
				} else {
					$line["content_preview"] =  "&mdash; " . truncate_string(strip_tags($line["content"]), 250);

					$max_excerpt_length = 250;

					PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_QUERY_HEADLINES,
						function ($result) use (&$line) {
							$line = $result;
						},
						$line, $max_excerpt_length);
				}

				$this->_mark_timestamp("   hook_query_headlines");

				$id = $line["id"];

				// frontend doesn't expect pdo returning booleans as strings on mysql
				if (DB_TYPE == "mysql") {
					foreach (["unread", "marked", "published"] as $k) {
						$line[$k] = $line[$k] === "1";
					}
				}

				// normalize archived feed
				if ($line['feed_id'] === null) {
					$line['feed_id'] = 0;
					$line["feed_title"] = __("Archived articles");
				}

				$feed_id = $line["feed_id"];

				$label_cache = $line["label_cache"];
				$labels = false;

				if ($label_cache) {
					$label_cache = json_decode($label_cache, true);

					if ($label_cache) {
						if ($label_cache["no-labels"] ?? false == 1)
							$labels = array();
						else
							$labels = $label_cache;
					}
				}

				if (!is_array($labels)) $labels = Article::_get_labels($id);

				$line["labels"] = Article::_get_labels($id);

				if (count($topmost_article_ids) < 3) {
					array_push($topmost_article_ids, $id);
				}

				$this->_mark_timestamp("   labels");

				$line["feed_title"] = $line["feed_title"] ?? "";

				$line["buttons_left"] = "";
				PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_ARTICLE_LEFT_BUTTON,
					function ($result) use (&$line) {
						$line["buttons_left"] .= $result;
					},
					$line);

				$line["buttons"] = "";
				PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_ARTICLE_BUTTON,
					function ($result) use (&$line) {
						$line["buttons"] .= $result;
					},
					$line);

				$this->_mark_timestamp("   pre-sanitize");

				$line["content"] = Sanitizer::sanitize($line["content"],
					$line['hide_images'], false, $line["site_url"], $highlight_words, $line["id"]);

				$this->_mark_timestamp("   sanitize");

				PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_RENDER_ARTICLE_CDM,
					function ($result, $plugin) use (&$line) {
						$line = $result;
						$this->_mark_timestamp("       hook_render_cdm: " . get_class($plugin));
					},
					$line);

				$this->_mark_timestamp("   hook_render_cdm");

				$line['content'] = DiskCache::rewrite_urls($line['content']);

				$this->_mark_timestamp("   disk_cache_rewrite");

				$this->_mark_timestamp("   note");

				if (!get_pref("CDM_EXPANDED")) {
					$line["cdm_excerpt"] = "<span class='collapse'>
						<i class='material-icons' onclick='return Article.cdmUnsetActive(event)'
								title=\"" . __("Collapse article") . "\">remove_circle</i></span>";

					if (get_pref('SHOW_CONTENT_PREVIEW')) {
						$line["cdm_excerpt"] .= "<span class='excerpt'>" . $line["content_preview"] . "</span>";
					}
				}

				$this->_mark_timestamp("   pre-enclosures");

				$line["enclosures"] = Article::_format_enclosures($id,
					$line["always_display_enclosures"],
					$line["content"],
					$line["hide_images"]);

				$this->_mark_timestamp("   enclosures");

				$line["updated_long"] = TimeHelper::make_local_datetime($line["updated"],true);
				$line["updated"] = TimeHelper::make_local_datetime($line["updated"], false, false, false, true);

				$line['imported'] = T_sprintf("Imported at %s",
					TimeHelper::make_local_datetime($line["date_entered"], false));

				$this->_mark_timestamp("   local-datetime");

				if ($line["tag_cache"])
					$tags = explode(",", $line["tag_cache"]);
				else
					$tags = false;

				$line["tags"] = Article::_get_tags($line["id"], false, $line["tag_cache"]);

				$this->_mark_timestamp("   tags");

				$line['has_icon'] = self::_has_icon($feed_id);

			    //setting feed headline background color, needs to change text color based on dark/light
				$fav_color = $line['favicon_avg_color'] ?? false;

				$this->_mark_timestamp("   pre-color");

				require_once "colors.php";

				if (!isset($rgba_cache[$feed_id])) {
					if ($fav_color && $fav_color != 'fail') {
						$rgba_cache[$feed_id] = \Colors\_color_unpack($fav_color);
					} else {
						$rgba_cache[$feed_id] = \Colors\_color_unpack($this->_color_of($line['feed_title']));
					}
				}

				if (isset($rgba_cache[$feed_id])) {
				    $line['feed_bg_color'] = 'rgba(' . implode(",", $rgba_cache[$feed_id]) . ',0.3)';
				}

				$this->_mark_timestamp("   color");

				/* we don't need those */

				foreach (["date_entered", "guid", "last_published", "last_marked", "tag_cache", "favicon_avg_color",
								"uuid", "label_cache", "yyiw"] as $k)
					unset($line[$k]);

				array_push($reply['content'], $line);

				$this->_mark_timestamp("article end");
			}
		}

		$this->_mark_timestamp("end of articles");

		if (!$headlines_count) {

			if ($result instanceof PDOStatement) {

				if ($query_error_override) {
					$message = $query_error_override;
				} else {
					switch ($view_mode) {
						case "unread":
							$message = __("No unread articles found to display.");
							break;
						case "updated":
							$message = __("No updated articles found to display.");
							break;
						case "marked":
							$message = __("No starred articles found to display.");
							break;
						default:
							if ($feed < LABEL_BASE_INDEX) {
								$message = __("No articles found to display. You can assign articles to labels manually from article header context menu (applies to all selected articles) or use a filter.");
							} else {
								$message = __("No articles found to display.");
							}
					}
				}

				if (!$offset && $message) {
					$reply['content'] = "<div class='whiteBox'>$message";

					$reply['content'] .= "<p><span class=\"text-muted\">";

					$sth = $this->pdo->prepare("SELECT " . SUBSTRING_FOR_DATE . "(MAX(last_updated), 1, 19) AS last_updated FROM ttrss_feeds
                        WHERE owner_uid = ?");
					$sth->execute([$_SESSION['uid']]);
					$row = $sth->fetch();

					$last_updated = TimeHelper::make_local_datetime($row["last_updated"], false);

					$reply['content'] .= sprintf(__("Feeds last updated at %s"), $last_updated);

					$sth = $this->pdo->prepare("SELECT COUNT(id) AS num_errors
                        FROM ttrss_feeds WHERE last_error != '' AND owner_uid = ?");
					$sth->execute([$_SESSION['uid']]);
					$row = $sth->fetch();

					$num_errors = $row["num_errors"];

					if ($num_errors > 0) {
						$reply['content'] .= "<br/>";
						$reply['content'] .= "<a class=\"text-muted\" href=\"#\" onclick=\"CommonDialogs.showFeedsWithErrors()\">" .
							__('Some feeds have update errors (click for details)') . "</a>";
					}
					$reply['content'] .= "</span></p></div>";

				}
			} else if (is_numeric($result) && $result == -1) {
				$reply['first_id_changed'] = true;
			}
		}

		$this->_mark_timestamp("end");

		return array($topmost_article_ids, $headlines_count, $feed, $disable_cache, $reply);
	}

	function catchupAll() {
		$sth = $this->pdo->prepare("UPDATE ttrss_user_entries SET
						last_read = NOW(), unread = false WHERE unread = true AND owner_uid = ?");
		$sth->execute([$_SESSION['uid']]);
	}

	function view() {
		$reply = array();

		$feed = $_REQUEST["feed"];
		$method = $_REQUEST["m"] ?? "";
		$view_mode = $_REQUEST["view_mode"];
		$limit = 30;
		$cat_view = $_REQUEST["cat"] == "true";
		$next_unread_feed = $_REQUEST["nuf"] ?? 0;
		$offset = $_REQUEST["skip"] ?? 0;
		$order_by = $_REQUEST["order_by"] ?? "";
		$check_first_id = $_REQUEST["fid"] ?? 0;

		if (is_numeric($feed)) $feed = (int) $feed;

		/* Feed -5 is a special case: it is used to display auxiliary information
		 * when there's nothing to load - e.g. no stuff in fresh feed */

		if ($feed == -5) {
			print json_encode($this->_generate_dashboard_feed());
			return;
		}

		$sth = false;
		if ($feed < LABEL_BASE_INDEX) {

			$label_feed = Labels::feed_to_label_id($feed);

			$sth = $this->pdo->prepare("SELECT id FROM ttrss_labels2 WHERE
							id = ? AND owner_uid = ?");
			$sth->execute([$label_feed, $_SESSION['uid']]);

		} else if (!$cat_view && is_numeric($feed) && $feed > 0) {

			$sth = $this->pdo->prepare("SELECT id FROM ttrss_feeds WHERE
							id = ? AND owner_uid = ?");
			$sth->execute([$feed, $_SESSION['uid']]);

		} else if ($cat_view && is_numeric($feed) && $feed > 0) {

			$sth = $this->pdo->prepare("SELECT id FROM ttrss_feed_categories WHERE
							id = ? AND owner_uid = ?");

			$sth->execute([$feed, $_SESSION['uid']]);
		}

		if ($sth && !$sth->fetch()) {
			print json_encode($this->_generate_error_feed(__("Feed not found.")));
			return;
		}

		set_pref("_DEFAULT_VIEW_MODE", $view_mode);
		set_pref("_DEFAULT_VIEW_ORDER_BY", $order_by);

		/* bump login timestamp if needed */
		if (time() - $_SESSION["last_login_update"] > 3600) {
			$sth = $this->pdo->prepare("UPDATE ttrss_users SET last_login = NOW() WHERE id = ?");
			$sth->execute([$_SESSION['uid']]);

			$_SESSION["last_login_update"] = time();
		}

		if (!$cat_view && is_numeric($feed) && $feed > 0) {
			$sth = $this->pdo->prepare("UPDATE ttrss_feeds SET last_viewed = NOW()
							WHERE id = ? AND owner_uid = ?");
			$sth->execute([$feed, $_SESSION['uid']]);
		}

		$reply['headlines'] = [];

		list($override_order, $skip_first_id_check) = self::_order_to_override_query($order_by);

		$ret = $this->_format_headlines_list($feed, $method,
			$view_mode, $limit, $cat_view, $offset,
			$override_order, true, $check_first_id, $skip_first_id_check, $order_by);

		$headlines_count = $ret[1];
		$disable_cache = $ret[3];
		$reply['headlines'] = $ret[4];

		if (!$next_unread_feed)
			$reply['headlines']['id'] = $feed;
		else
			$reply['headlines']['id'] = $next_unread_feed;

		$reply['headlines']['is_cat'] = $cat_view;

		$reply['headlines-info'] = ["count" => (int) $headlines_count,
            						"disable_cache" => (bool) $disable_cache];

		// this is parsed by handleRpcJson() on first viewfeed() to set cdm expanded, etc
		$reply['runtime-info'] = RPC::make_runtime_info();

		$reply_json = json_encode($reply);

		if (!$reply_json) {
		    $reply_json = json_encode(["error" => ["code" => 15,
                "message" => json_last_error_msg()]]);
        }

		print $reply_json;

	}

	private function _generate_dashboard_feed() {
		$reply = array();

		$reply['headlines']['id'] = -5;
		$reply['headlines']['is_cat'] = false;

		$reply['headlines']['toolbar'] = '';

		$reply['headlines']['content'] = "<div class='whiteBox'>".__('No feed selected.');

		$reply['headlines']['content'] .= "<p><span class=\"text-muted\">";

		$sth = $this->pdo->prepare("SELECT ".SUBSTRING_FOR_DATE."(MAX(last_updated), 1, 19) AS last_updated FROM ttrss_feeds
			WHERE owner_uid = ?");
		$sth->execute([$_SESSION['uid']]);
		$row = $sth->fetch();

		$last_updated = TimeHelper::make_local_datetime($row["last_updated"], false);

		$reply['headlines']['content'] .= sprintf(__("Feeds last updated at %s"), $last_updated);

		$sth = $this->pdo->prepare("SELECT COUNT(id) AS num_errors
			FROM ttrss_feeds WHERE last_error != '' AND owner_uid = ?");
		$sth->execute([$_SESSION['uid']]);
		$row = $sth->fetch();

		$num_errors = $row["num_errors"];

		if ($num_errors > 0) {
			$reply['headlines']['content'] .= "<br/>";
			$reply['headlines']['content'] .= "<a class=\"text-muted\" href=\"#\" onclick=\"CommonDialogs.showFeedsWithErrors()\">".
				__('Some feeds have update errors (click for details)')."</a>";
		}
		$reply['headlines']['content'] .= "</span></p>";

		$reply['headlines-info'] = array("count" => 0,
			"unread" => 0,
			"disable_cache" => true);

		return $reply;
	}

	private function _generate_error_feed($error) {
		$reply = array();

		$reply['headlines']['id'] = -7;
		$reply['headlines']['is_cat'] = false;

		$reply['headlines']['toolbar'] = '';
		$reply['headlines']['content'] = "<div class='whiteBox'>". $error . "</div>";

		$reply['headlines-info'] = array("count" => 0,
			"unread" => 0,
			"disable_cache" => true);

		return $reply;
	}

	function subscribeToFeed() {
		print json_encode([
			"cat_select" => \Controls\select_feeds_cats("cat")
		]);
	}

	function search() {
		print json_encode([
			"show_language" => DB_TYPE == "pgsql",
			"show_syntax_help" => count(PluginHost::getInstance()->get_hooks(PluginHost::HOOK_SEARCH)) == 0,
			"all_languages" => Pref_Feeds::get_ts_languages(),
			"default_language" => get_pref('DEFAULT_SEARCH_LANGUAGE')
		]);
	}

	function updatedebugger() {
		header("Content-type: text/html");

		$xdebug = isset($_REQUEST["xdebug"]) ? (int)$_REQUEST["xdebug"] : 1;

		Debug::set_enabled(true);
		Debug::set_loglevel($xdebug);

		$feed_id = (int)$_REQUEST["feed_id"];
		$do_update = ($_REQUEST["action"] ?? "") == "do_update";
		$csrf_token = $_POST["csrf_token"];

		$sth = $this->pdo->prepare("SELECT id FROM ttrss_feeds WHERE id = ? AND owner_uid = ?");
		$sth->execute([$feed_id, $_SESSION['uid']]);

		if (!$sth->fetch()) {
		    print "Access denied.";
		    return;
        }
		?>
		<!DOCTYPE html>
		<html>
		<head>
			<title>Feed Debugger</title>
			<style type='text/css'>
				@media (prefers-color-scheme: dark) {
					body {
						background : #222;
					}
				}
				body.css_loading * {
					display : none;
				}
			</style>
			<script>
				dojoConfig = {
					async: true,
					cacheBust: "<?= get_scripts_timestamp(); ?>",
					packages: [
						{ name: "fox", location: "../../js" },
					]
				};
			</script>
			<?= javascript_tag("js/utility.js") ?>
			<?= javascript_tag("js/common.js") ?>
			<?= javascript_tag("lib/dojo/dojo.js") ?>
			<?= javascript_tag("lib/dojo/tt-rss-layer.js") ?>
		</head>
		<body class="flat ttrss_utility feed_debugger css_loading">
		<script type="text/javascript">
			require(['dojo/parser', "dojo/ready", 'dijit/form/Button','dijit/form/CheckBox', 'fox/form/Select', 'dijit/form/Form',
				'dijit/form/Select','dijit/form/TextBox','dijit/form/ValidationTextBox'],function(parser, ready){
				ready(function() {
					parser.parse();
				});
			});
		</script>

			<div class="container">
				<h1>Feed Debugger: <?= "$feed_id: " . $this->_get_title($feed_id) ?></h1>
				<div class="content">
					<form method="post" action="" dojoType="dijit.form.Form">
						<?= \Controls\hidden_tag("op", "feeds") ?>
						<?= \Controls\hidden_tag("method", "updatedebugger") ?>
						<?= \Controls\hidden_tag("csrf_token", $csrf_token) ?>
						<?= \Controls\hidden_tag("action", "do_update") ?>
						<?= \Controls\hidden_tag("feed_id", (string)$feed_id) ?>

						<fieldset>
							<label>
							<?= \Controls\select_hash("xdebug", $xdebug,
									[Debug::$LOG_VERBOSE => "LOG_VERBOSE", Debug::$LOG_EXTENDED => "LOG_EXTENDED"]);
							?></label>
						</fieldset>

						<fieldset>
							<label class="checkbox"><?= \Controls\checkbox_tag("force_refetch", isset($_REQUEST["force_refetch"])) ?> Force refetch</label>
						</fieldset>

						<fieldset class="narrow">
							<label class="checkbox"><?= \Controls\checkbox_tag("force_rehash", isset($_REQUEST["force_rehash"])) ?> Force rehash</label>
						</fieldset>

						<?= \Controls\submit_tag("Continue") ?>
					</form>

					<hr>

					<pre><?php

					if ($do_update) {
						RSSUtils::update_rss_feed($feed_id, true);
					}

					?></pre>
				</div>
			</div>
		</body>
		</html>
		<?php

	}

	static function _catchup($feed, $cat_view, $owner_uid = false, $mode = 'all', $search = false) {

		if (!$owner_uid) $owner_uid = $_SESSION['uid'];

		$pdo = Db::pdo();

		if (is_array($search) && $search[0]) {
			$search_qpart = "";

			PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_SEARCH,
				function ($result) use (&$search_qpart, &$search_words) {
					if (!empty($result)) {
						list($search_qpart, $search_words) = $result;
						return true;
					}
				},
				$search[0]);

			// fall back in case of no plugins
			if (empty($search_qpart)) {
				list($search_qpart, $search_words) = self::_search_to_sql($search[0], $search[1], $owner_uid);
			}
		} else {
			$search_qpart = "true";
		}

		// TODO: all this interval stuff needs some generic generator function

		switch ($mode) {
			case "1day":
				if (DB_TYPE == "pgsql") {
					$date_qpart = "date_entered < NOW() - INTERVAL '1 day' ";
				} else {
					$date_qpart = "date_entered < DATE_SUB(NOW(), INTERVAL 1 DAY) ";
				}
				break;
			case "1week":
				if (DB_TYPE == "pgsql") {
					$date_qpart = "date_entered < NOW() - INTERVAL '1 week' ";
				} else {
					$date_qpart = "date_entered < DATE_SUB(NOW(), INTERVAL 1 WEEK) ";
				}
				break;
			case "2week":
				if (DB_TYPE == "pgsql") {
					$date_qpart = "date_entered < NOW() - INTERVAL '2 week' ";
				} else {
					$date_qpart = "date_entered < DATE_SUB(NOW(), INTERVAL 2 WEEK) ";
				}
				break;
			default:
				$date_qpart = "true";
		}

		if (is_numeric($feed)) {
			if ($cat_view) {

				if ($feed >= 0) {

					if ($feed > 0) {
						$children = self::_get_child_cats($feed, $owner_uid);
						array_push($children, $feed);
						$children = array_map("intval", $children);

						$children = join(",", $children);

						$cat_qpart = "cat_id IN ($children)";
					} else {
						$cat_qpart = "cat_id IS NULL";
					}

					$sth = $pdo->prepare("UPDATE ttrss_user_entries
						SET unread = false, last_read = NOW() WHERE ref_id IN
							(SELECT id FROM
								(SELECT DISTINCT id FROM ttrss_entries, ttrss_user_entries WHERE ref_id = id
									AND owner_uid = ? AND unread = true AND feed_id IN
										(SELECT id FROM ttrss_feeds WHERE $cat_qpart) AND $date_qpart AND $search_qpart) as tmp)");
					$sth->execute([$owner_uid]);

				} else if ($feed == -2) {

					$sth = $pdo->prepare("UPDATE ttrss_user_entries
						SET unread = false,last_read = NOW() WHERE (SELECT COUNT(*)
							FROM ttrss_user_labels2, ttrss_entries WHERE article_id = ref_id AND id = ref_id AND $date_qpart AND $search_qpart) > 0
							AND unread = true AND owner_uid = ?");
					$sth->execute([$owner_uid]);
				}

			} else if ($feed > 0) {

				$sth = $pdo->prepare("UPDATE ttrss_user_entries
					SET unread = false, last_read = NOW() WHERE ref_id IN
						(SELECT id FROM
							(SELECT DISTINCT id FROM ttrss_entries, ttrss_user_entries WHERE ref_id = id
								AND owner_uid = ? AND unread = true AND feed_id = ? AND $date_qpart AND $search_qpart) as tmp)");
				$sth->execute([$owner_uid, $feed]);

			} else if ($feed < 0 && $feed > LABEL_BASE_INDEX) { // special, like starred

				if ($feed == -1) {
					$sth = $pdo->prepare("UPDATE ttrss_user_entries
						SET unread = false, last_read = NOW() WHERE ref_id IN
							(SELECT id FROM
								(SELECT DISTINCT id FROM ttrss_entries, ttrss_user_entries WHERE ref_id = id
									AND owner_uid = ? AND unread = true AND marked = true AND $date_qpart AND $search_qpart) as tmp)");
					$sth->execute([$owner_uid]);
				}

				if ($feed == -2) {
					$sth = $pdo->prepare("UPDATE ttrss_user_entries
						SET unread = false, last_read = NOW() WHERE ref_id IN
							(SELECT id FROM
								(SELECT DISTINCT id FROM ttrss_entries, ttrss_user_entries WHERE ref_id = id
									AND owner_uid = ? AND unread = true AND published = true AND $date_qpart AND $search_qpart) as tmp)");
					$sth->execute([$owner_uid]);
				}

				if ($feed == -3) {

					$intl = (int) get_pref("FRESH_ARTICLE_MAX_AGE");

					if (DB_TYPE == "pgsql") {
						$match_part = "date_entered > NOW() - INTERVAL '$intl hour' ";
					} else {
						$match_part = "date_entered > DATE_SUB(NOW(),
							INTERVAL $intl HOUR) ";
					}

					$sth = $pdo->prepare("UPDATE ttrss_user_entries
						SET unread = false, last_read = NOW() WHERE ref_id IN
							(SELECT id FROM
								(SELECT DISTINCT id FROM ttrss_entries, ttrss_user_entries WHERE ref_id = id
									AND owner_uid = ? AND score >= 0 AND unread = true AND $date_qpart AND $match_part AND $search_qpart) as tmp)");
					$sth->execute([$owner_uid]);
				}

				if ($feed == -4) {
					$sth = $pdo->prepare("UPDATE ttrss_user_entries
						SET unread = false, last_read = NOW() WHERE ref_id IN
							(SELECT id FROM
								(SELECT DISTINCT id FROM ttrss_entries, ttrss_user_entries WHERE ref_id = id
									AND owner_uid = ? AND unread = true AND $date_qpart AND $search_qpart) as tmp)");
					$sth->execute([$owner_uid]);
				}

			} else if ($feed < LABEL_BASE_INDEX) { // label

				$label_id = Labels::feed_to_label_id($feed);

				$sth = $pdo->prepare("UPDATE ttrss_user_entries
					SET unread = false, last_read = NOW() WHERE ref_id IN
						(SELECT id FROM
							(SELECT DISTINCT ttrss_entries.id FROM ttrss_entries, ttrss_user_entries, ttrss_user_labels2 WHERE ref_id = id
								AND label_id = ? AND ref_id = article_id
								AND owner_uid = ? AND unread = true AND $date_qpart AND $search_qpart) as tmp)");
				$sth->execute([$label_id, $owner_uid]);

			}

		} else { // tag
			$sth = $pdo->prepare("UPDATE ttrss_user_entries
				SET unread = false, last_read = NOW() WHERE ref_id IN
					(SELECT id FROM
						(SELECT DISTINCT ttrss_entries.id FROM ttrss_entries, ttrss_user_entries, ttrss_tags WHERE ref_id = ttrss_entries.id
							AND post_int_id = int_id AND tag_name = ?
							AND ttrss_user_entries.owner_uid = ? AND unread = true AND $date_qpart AND $search_qpart) as tmp)");
			$sth->execute([$feed, $owner_uid]);

		}
	}

	static function _get_counters($feed, $is_cat = false, $unread_only = false,
							 $owner_uid = false) {

		$n_feed = (int) $feed;
		$need_entries = false;

		$pdo = Db::pdo();

		if (!$owner_uid) $owner_uid = $_SESSION["uid"];

		if ($unread_only) {
			$unread_qpart = "unread = true";
		} else {
			$unread_qpart = "true";
		}

		$match_part = "";

		if ($is_cat) {
			return self::_get_cat_unread($n_feed, $owner_uid);
		} else if ($n_feed == -6) {
			return 0;
		} else if ($feed != "0" && $n_feed == 0) {

			$sth = $pdo->prepare("SELECT SUM((SELECT COUNT(int_id)
				FROM ttrss_user_entries,ttrss_entries WHERE int_id = post_int_id
					AND ref_id = id AND $unread_qpart)) AS count FROM ttrss_tags
				WHERE owner_uid = ? AND tag_name = ?");

			$sth->execute([$owner_uid, $feed]);
			$row = $sth->fetch();

			return $row["count"];

		} else if ($n_feed == -1) {
			$match_part = "marked = true";
		} else if ($n_feed == -2) {
			$match_part = "published = true";
		} else if ($n_feed == -3) {
			$match_part = "unread = true AND score >= 0";

			$intl = (int) get_pref("FRESH_ARTICLE_MAX_AGE", $owner_uid);

			if (DB_TYPE == "pgsql") {
				$match_part .= " AND date_entered > NOW() - INTERVAL '$intl hour' ";
			} else {
				$match_part .= " AND date_entered > DATE_SUB(NOW(), INTERVAL $intl HOUR) ";
			}

			$need_entries = true;

		} else if ($n_feed == -4) {
			$match_part = "true";
		} else if ($n_feed >= 0) {

			if ($n_feed != 0) {
				$match_part = sprintf("feed_id = %d", $n_feed);
			} else {
				$match_part = "feed_id IS NULL";
			}

		} else if ($feed < LABEL_BASE_INDEX) {

			$label_id = Labels::feed_to_label_id($feed);

			return self::_get_label_unread($label_id, $owner_uid);
		}

		if ($match_part) {

			if ($need_entries) {
				$from_qpart = "ttrss_user_entries,ttrss_entries";
				$from_where = "ttrss_entries.id = ttrss_user_entries.ref_id AND";
			} else {
				$from_qpart = "ttrss_user_entries";
				$from_where = "";
			}

			$sth = $pdo->prepare("SELECT count(int_id) AS unread
				FROM $from_qpart WHERE
				$unread_qpart AND $from_where ($match_part) AND ttrss_user_entries.owner_uid = ?");
			$sth->execute([$owner_uid]);
			$row = $sth->fetch();

			return $row["unread"];

		} else {

			$sth = $pdo->prepare("SELECT COUNT(post_int_id) AS unread
				FROM ttrss_tags,ttrss_user_entries,ttrss_entries
				WHERE tag_name = ? AND post_int_id = int_id AND ref_id = ttrss_entries.id
				AND $unread_qpart AND ttrss_tags.owner_uid = ,");

			$sth->execute([$feed, $owner_uid]);
			$row = $sth->fetch();

			return $row["unread"];
		}
	}

	function add() {
		$feed = clean($_REQUEST['feed']);
		$cat = clean($_REQUEST['cat']);
		$need_auth = isset($_REQUEST['need_auth']);
		$login = $need_auth ? clean($_REQUEST['login']) : '';
		$pass = $need_auth ? clean($_REQUEST['pass']) : '';

		$rc = Feeds::_subscribe($feed, $cat, $login, $pass);

		print json_encode(array("result" => $rc));
	}

	/**
	 * @return array (code => Status code, message => error message if available)
	 *
	 *                 0 - OK, Feed already exists
	 *                 1 - OK, Feed added
	 *                 2 - Invalid URL
	 *                 3 - URL content is HTML, no feeds available
	 *                 4 - URL content is HTML which contains multiple feeds.
	 *                     Here you should call extractfeedurls in rpc-backend
	 *                     to get all possible feeds.
	 *                 5 - Couldn't download the URL content.
	 *                 6 - Content is an invalid XML.
	 */
	static function _subscribe($url, $cat_id = 0,
							   $auth_login = '', $auth_pass = '') {

		global $fetch_last_error;
		global $fetch_last_error_content;
		global $fetch_last_content_type;

		$pdo = Db::pdo();

		$url = UrlHelper::validate($url);

		if (!$url) return array("code" => 2);

		$contents = @UrlHelper::fetch($url, false, $auth_login, $auth_pass);

		PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_SUBSCRIBE_FEED,
			function ($result) use (&$contents) {
				$contents = $result;
			},
			$contents, $url, $auth_login, $auth_pass);

		if (empty($contents)) {
			if (preg_match("/cloudflare\.com/", $fetch_last_error_content)) {
				$fetch_last_error .= " (feed behind Cloudflare)";
			}

			return array("code" => 5, "message" => $fetch_last_error);
		}

		if (mb_strpos($fetch_last_content_type, "html") !== false && self::_is_html($contents)) {
			$feedUrls = self::_get_feeds_from_html($url, $contents);

			if (count($feedUrls) == 0) {
				return array("code" => 3);
			} else if (count($feedUrls) > 1) {
				return array("code" => 4, "feeds" => $feedUrls);
			}
			//use feed url as new URL
			$url = key($feedUrls);
		}

		if (!$cat_id) $cat_id = null;

		$sth = $pdo->prepare("SELECT id FROM ttrss_feeds
			WHERE feed_url = ? AND owner_uid = ?");
		$sth->execute([$url, $_SESSION['uid']]);

		if ($row = $sth->fetch()) {
			return array("code" => 0, "feed_id" => (int) $row["id"]);
		} else {
			$sth = $pdo->prepare(
				"INSERT INTO ttrss_feeds
					(owner_uid,feed_url,title,cat_id, auth_login,auth_pass,update_method,auth_pass_encrypted)
				VALUES (?, ?, ?, ?, ?, ?, 0, false)");

			$sth->execute([$_SESSION['uid'], $url, "[Unknown]", $cat_id, (string)$auth_login, (string)$auth_pass]);

			$sth = $pdo->prepare("SELECT id FROM ttrss_feeds WHERE feed_url = ?
					AND owner_uid = ?");
			$sth->execute([$url, $_SESSION['uid']]);
			$row = $sth->fetch();

			$feed_id = $row["id"];

			if ($feed_id) {
				RSSUtils::set_basic_feed_info($feed_id);
			}

			return array("code" => 1, "feed_id" => (int) $feed_id);

		}
	}

	static function _get_icon_file($feed_id) {
		return ICONS_DIR . "/$feed_id.ico";
	}

	static function _has_icon($id) {
		return is_file(ICONS_DIR . "/$id.ico") && filesize(ICONS_DIR . "/$id.ico") > 0;
	}

	static function _get_icon($id) {
		switch ($id) {
			case 0:
				return "archive";
				break;
			case -1:
				return "star";
				break;
			case -2:
				return "rss_feed";
				break;
			case -3:
				return "whatshot";
				break;
			case -4:
				return "inbox";
				break;
			case -6:
				return "restore";
				break;
			default:
				if ($id < LABEL_BASE_INDEX) {
					return "label";
				} else {
					$icon = self::_get_icon_file($id);

                    if ($icon && file_exists($icon)) {
						return ICONS_URL . "/" . basename($icon) . "?" . filemtime($icon);
					}
				}
				break;
		}

		return false;
	}

	static function _find_by_url($feed_url, $owner_uid) {
		$sth = Db::pdo()->prepare("SELECT id FROM ttrss_feeds WHERE
			feed_url = ? AND owner_uid = ?");
		$sth->execute([$feed_url, $owner_uid]);

		if ($row = $sth->fetch()) {
			return $row["id"];
		}

		return false;
	}

	static function _get_title($id, $cat = false) {
	    $pdo = Db::pdo();

		if ($cat) {
			return self::_get_cat_title($id);
		} else if ($id == -1) {
			return __("Starred articles");
		} else if ($id == -2) {
			return __("Published articles");
		} else if ($id == -3) {
			return __("Fresh articles");
		} else if ($id == -4) {
			return __("All articles");
		} else if ($id === 0 || $id === "0") {
			return __("Archived articles");
		} else if ($id == -6) {
			return __("Recently read");
		} else if ($id < LABEL_BASE_INDEX) {

			$label_id = Labels::feed_to_label_id($id);

			$sth = $pdo->prepare("SELECT caption FROM ttrss_labels2 WHERE id = ?");
			$sth->execute([$label_id]);

			if ($row = $sth->fetch()) {
				return $row["caption"];
			} else {
				return "Unknown label ($label_id)";
			}

		} else if (is_numeric($id) && $id > 0) {

		    $sth = $pdo->prepare("SELECT title FROM ttrss_feeds WHERE id = ?");
		    $sth->execute([$id]);

		    if ($row = $sth->fetch()) {
				return $row["title"];
			} else {
				return "Unknown feed ($id)";
			}

		} else {
			return $id;
		}
	}

	// only real cats
	static function _get_cat_marked($cat, $owner_uid = false) {

		if (!$owner_uid) $owner_uid = $_SESSION["uid"];

		$pdo = Db::pdo();

		if ($cat >= 0) {

			$sth = $pdo->prepare("SELECT SUM(CASE WHEN marked THEN 1 ELSE 0 END) AS marked
				FROM ttrss_user_entries
				WHERE feed_id IN (SELECT id FROM ttrss_feeds
                    WHERE (cat_id = :cat OR (:cat IS NULL AND cat_id IS NULL))
					AND owner_uid = :uid)
				AND owner_uid = :uid");
			$sth->execute(["cat" => $cat ? $cat : null, "uid" => $owner_uid]);
			$row = $sth->fetch();

			return $row["marked"];
		} else {
			return 0;
		}
	}

	static function _get_cat_unread($cat, $owner_uid = false) {

		if (!$owner_uid) $owner_uid = $_SESSION["uid"];

		$pdo = Db::pdo();

		if ($cat >= 0) {

			$sth = $pdo->prepare("SELECT SUM(CASE WHEN unread THEN 1 ELSE 0 END) AS unread
				FROM ttrss_user_entries
				WHERE feed_id IN (SELECT id FROM ttrss_feeds
                    WHERE (cat_id = :cat OR (:cat IS NULL AND cat_id IS NULL))
					AND owner_uid = :uid)
				AND owner_uid = :uid");
			$sth->execute(["cat" => $cat ? $cat : null, "uid" => $owner_uid]);
			$row = $sth->fetch();

			return $row["unread"];

		} else if ($cat == -1) {
			return 0;
		} else if ($cat == -2) {

			$sth = $pdo->prepare("SELECT COUNT(DISTINCT article_id) AS unread
				FROM ttrss_user_entries ue, ttrss_user_labels2 l
				WHERE article_id = ref_id AND unread IS true AND ue.owner_uid = :uid");
			$sth->execute(["uid" => $owner_uid]);
            $row = $sth->fetch();

			return $row["unread"];
		}
	}

	// only accepts real cats (>= 0)
	static function _get_cat_children_unread($cat, $owner_uid = false) {
		if (!$owner_uid) $owner_uid = $_SESSION["uid"];

		$pdo = Db::pdo();

		$sth = $pdo->prepare("SELECT id FROM ttrss_feed_categories WHERE parent_cat = ?
				AND owner_uid = ?");
		$sth->execute([$cat, $owner_uid]);

		$unread = 0;

		while ($line = $sth->fetch()) {
			$unread += self::_get_cat_unread($line["id"], $owner_uid);
			$unread += self::_get_cat_children_unread($line["id"], $owner_uid);
		}

		return $unread;
	}

	static function _get_global_unread($user_id = false) {

		if (!$user_id) $user_id = $_SESSION["uid"];

		$pdo = Db::pdo();

		$sth = $pdo->prepare("SELECT SUM(CASE WHEN unread THEN 1 ELSE 0 END) AS count
			FROM ttrss_user_entries ue
			WHERE ue.owner_uid = ?");

		$sth->execute([$user_id]);
		$row = $sth->fetch();

		return $row["count"];
	}

	static function _get_cat_title($cat_id) {

		if ($cat_id == -1) {
			return __("Special");
		} else if ($cat_id == -2) {
			return __("Labels");
		} else {

		    $pdo = Db::pdo();

			$sth = $pdo->prepare("SELECT title FROM ttrss_feed_categories WHERE
				id = ?");
			$sth->execute([$cat_id]);

			if ($row = $sth->fetch()) {
				return $row["title"];
			} else {
				return __("Uncategorized");
			}
		}
	}

	private static function _get_label_unread($label_id, $owner_uid = false) {
		if (!$owner_uid) $owner_uid = $_SESSION["uid"];

		$pdo = Db::pdo();

		$sth = $pdo->prepare("SELECT COUNT(ref_id) AS unread FROM ttrss_user_entries, ttrss_user_labels2
			WHERE owner_uid = ? AND unread = true AND label_id = ? AND article_id = ref_id");

		$sth->execute([$owner_uid, $label_id]);

		if ($row = $sth->fetch()) {
			return $row["unread"];
		} else {
			return 0;
		}
	}

	static function _get_headlines($params) {

		$pdo = Db::pdo();

		// WARNING: due to highly dynamic nature of this query its going to quote parameters
		// right before adding them to SQL part

		$feed = $params["feed"];
		$limit = isset($params["limit"]) ? $params["limit"] : 30;
		$view_mode = $params["view_mode"];
		$cat_view = isset($params["cat_view"]) ? $params["cat_view"] : false;
		$search = isset($params["search"]) ? $params["search"] : false;
		$search_language = isset($params["search_language"]) ? $params["search_language"] : "";
		$override_order = isset($params["override_order"]) ? $params["override_order"] : false;
		$offset = isset($params["offset"]) ? $params["offset"] : 0;
		$owner_uid = isset($params["owner_uid"]) ? $params["owner_uid"] : $_SESSION["uid"];
		$since_id = isset($params["since_id"]) ? $params["since_id"] : 0;
		$include_children = isset($params["include_children"]) ? $params["include_children"] : false;
		$ignore_vfeed_group = isset($params["ignore_vfeed_group"]) ? $params["ignore_vfeed_group"] : false;
		$override_strategy = isset($params["override_strategy"]) ? $params["override_strategy"] : false;
		$override_vfeed = isset($params["override_vfeed"]) ? $params["override_vfeed"] : false;
		$start_ts = isset($params["start_ts"]) ? $params["start_ts"] : false;
		$check_first_id = isset($params["check_first_id"]) ? $params["check_first_id"] : false;
		$skip_first_id_check = isset($params["skip_first_id_check"]) ? $params["skip_first_id_check"] : false;
		//$order_by = isset($params["order_by"]) ? $params["order_by"] : false;

		$ext_tables_part = "";
		$limit_query_part = "";
		$query_error_override = "";

		$search_words = [];

		if ($search) {
			$search_query_part = "";

			PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_SEARCH,
				function ($result) use (&$search_query_part, &$search_words) {
					if (!empty($result)) {
						list($search_query_part, $search_words) = $result;
						return true;
					}
				},
				$search);

			// fall back in case of no plugins
			if (!$search_query_part) {
				list($search_query_part, $search_words) = self::_search_to_sql($search, $search_language, $owner_uid);
			}

			if (DB_TYPE == "pgsql") {
				$test_sth = $pdo->prepare("select $search_query_part
					FROM ttrss_entries, ttrss_user_entries WHERE id = ref_id limit 1");

				try {
					$test_sth->execute();
				} catch (PDOException $e) {
					// looks like tsquery syntax is invalid
					$search_query_part = "false";

					$query_error_override = T_sprintf("Incorrect search syntax: %s.", implode(" ", $search_words));
				}
			}

			$search_query_part .= " AND ";
		} else {
			$search_query_part = "";
		}

		if ($since_id) {
			$since_id_part = "ttrss_entries.id > ".$pdo->quote($since_id)." AND ";
		} else {
			$since_id_part = "";
		}

		$view_query_part = "";

		if ($view_mode == "adaptive") {
			if ($search) {
				$view_query_part = " ";
			} else if ($feed != -1) {

				$unread = getFeedUnread($feed, $cat_view);

				if ($cat_view && $feed > 0 && $include_children)
					$unread += self::_get_cat_children_unread($feed);

				if ($unread > 0) {
					$view_query_part = " unread = true AND ";
				}
			}
		}

		if ($view_mode == "marked") {
			$view_query_part = " marked = true AND ";
		}

		if ($view_mode == "has_note") {
			$view_query_part = " (note IS NOT NULL AND note != '') AND ";
		}

		if ($view_mode == "published") {
			$view_query_part = " published = true AND ";
		}

		if ($view_mode == "unread" && $feed != -6) {
			$view_query_part = " unread = true AND ";
		}

		if ($limit > 0) {
			$limit_query_part = "LIMIT " . (int)$limit;
		}

		$allow_archived = false;

		$vfeed_query_part = "";

		/* tags */
		if (!is_numeric($feed)) {
			$query_strategy_part = "true";
			$vfeed_query_part = "(SELECT title FROM ttrss_feeds WHERE
					id = feed_id) as feed_title,";
		} else if ($feed > 0) {

			if ($cat_view) {

				if ($feed > 0) {
					if ($include_children) {
						# sub-cats
						$subcats = self::_get_child_cats($feed, $owner_uid);
						array_push($subcats, $feed);
						$subcats = array_map("intval", $subcats);

						$query_strategy_part = "cat_id IN (".
							implode(",", $subcats).")";

					} else {
						$query_strategy_part = "cat_id = " . $pdo->quote((string)$feed);
					}

				} else {
					$query_strategy_part = "cat_id IS NULL";
				}

				$vfeed_query_part = "ttrss_feeds.title AS feed_title,";

			} else {
				$query_strategy_part = "feed_id = " . $pdo->quote((string)$feed);
			}
		} else if ($feed == 0 && !$cat_view) { // archive virtual feed
			$query_strategy_part = "feed_id IS NULL";
			$allow_archived = true;
		} else if ($feed == 0 && $cat_view) { // uncategorized
			$query_strategy_part = "cat_id IS NULL AND feed_id IS NOT NULL";
			$vfeed_query_part = "ttrss_feeds.title AS feed_title,";
		} else if ($feed == -1) { // starred virtual feed
			$query_strategy_part = "marked = true";
			$vfeed_query_part = "ttrss_feeds.title AS feed_title,";
			$allow_archived = true;

			if (!$override_order) {
				$override_order = "last_marked DESC, date_entered DESC, updated DESC";
			}

		} else if ($feed == -2) { // published virtual feed OR labels category

			if (!$cat_view) {
				$query_strategy_part = "published = true";
				$vfeed_query_part = "ttrss_feeds.title AS feed_title,";
				$allow_archived = true;

				if (!$override_order) {
					$override_order = "last_published DESC, date_entered DESC, updated DESC";
				}

			} else {
				$vfeed_query_part = "ttrss_feeds.title AS feed_title,";

				$ext_tables_part = "ttrss_labels2,ttrss_user_labels2,";

				$query_strategy_part = "ttrss_labels2.id = ttrss_user_labels2.label_id AND
						ttrss_user_labels2.article_id = ref_id";

			}
		} else if ($feed == -6) { // recently read
			$query_strategy_part = "unread = false AND last_read IS NOT NULL";

			if (DB_TYPE == "pgsql") {
				$query_strategy_part .= " AND last_read > NOW() - INTERVAL '1 DAY' ";
			} else {
				$query_strategy_part .= " AND last_read > DATE_SUB(NOW(), INTERVAL 1 DAY) ";
			}

			$vfeed_query_part = "ttrss_feeds.title AS feed_title,";
			$allow_archived = true;
			$ignore_vfeed_group = true;

			if (!$override_order) $override_order = "last_read DESC";

		} else if ($feed == -3) { // fresh virtual feed
			$query_strategy_part = "unread = true AND score >= 0";

			$intl = (int) get_pref("FRESH_ARTICLE_MAX_AGE", $owner_uid);

			if (DB_TYPE == "pgsql") {
				$query_strategy_part .= " AND date_entered > NOW() - INTERVAL '$intl hour' ";
			} else {
				$query_strategy_part .= " AND date_entered > DATE_SUB(NOW(), INTERVAL $intl HOUR) ";
			}

			$vfeed_query_part = "ttrss_feeds.title AS feed_title,";
		} else if ($feed == -4) { // all articles virtual feed
			$allow_archived = true;
			$query_strategy_part = "true";
			$vfeed_query_part = "ttrss_feeds.title AS feed_title,";
		} else if ($feed <= LABEL_BASE_INDEX) { // labels
			$label_id = Labels::feed_to_label_id($feed);

			$query_strategy_part = "label_id = ".$pdo->quote($label_id)." AND
					ttrss_labels2.id = ttrss_user_labels2.label_id AND
					ttrss_user_labels2.article_id = ref_id";

			$vfeed_query_part = "ttrss_feeds.title AS feed_title,";
			$ext_tables_part = "ttrss_labels2,ttrss_user_labels2,";
			$allow_archived = true;

		} else {
			$query_strategy_part = "true";
		}

		$order_by = "score DESC, date_entered DESC, updated DESC";

		if ($override_order) {
			$order_by = $override_order;
		}

		if ($override_strategy) {
			$query_strategy_part = $override_strategy;
		}

		if ($override_vfeed) {
			$vfeed_query_part = $override_vfeed;
		}

		$feed_title = "";
		$feed_site_url = "";
		$last_error = "";
		$last_updated = "";

		if ($search) {
			$feed_title = T_sprintf("Search results: %s", $search);
		} else {
			if ($cat_view) {
				$feed_title = self::_get_cat_title($feed);
			} else {
				if (is_numeric($feed) && $feed > 0) {
					$ssth = $pdo->prepare("SELECT title,site_url,last_error,last_updated
							FROM ttrss_feeds WHERE id = ? AND owner_uid = ?");
					$ssth->execute([$feed, $owner_uid]);
                    $row = $ssth->fetch();

					$feed_title = $row["title"];
					$feed_site_url = $row["site_url"];
					$last_error = $row["last_error"];
					$last_updated = $row["last_updated"];
				} else {
					$feed_title = self::_get_title($feed);
				}
			}
		}

		$content_query_part = "content, ";

		if ($limit_query_part) {
			$offset_query_part = "OFFSET " . (int)$offset;
		} else {
			$offset_query_part = "";
		}

		if ($start_ts) {
			$start_ts_formatted = date("Y/m/d H:i:s", strtotime($start_ts));
			$start_ts_query_part = "date_entered >= '$start_ts_formatted' AND";
		} else {
			$start_ts_query_part = "";
		}

		$first_id = 0;

		if (is_numeric($feed)) {
			// proper override_order applied above
			if ($vfeed_query_part && !$ignore_vfeed_group && get_pref('VFEED_GROUP_BY_FEED', $owner_uid)) {

				if (!(in_array($feed, self::NEVER_GROUP_BY_DATE) && !$cat_view)) {
					$yyiw_desc = $order_by == "date_reverse" ? "" : "desc";
					$yyiw_order_qpart = "yyiw $yyiw_desc, ";
				} else {
					$yyiw_order_qpart = "";
				}

				if (!$override_order) {
					$order_by = "$yyiw_order_qpart ttrss_feeds.title, $order_by";
				} else {
					$order_by = "$yyiw_order_qpart ttrss_feeds.title, $override_order";
				}
			}

			if (!$allow_archived) {
				$from_qpart = "${ext_tables_part}ttrss_entries LEFT JOIN ttrss_user_entries ON (ref_id = ttrss_entries.id),ttrss_feeds";
				$feed_check_qpart = "ttrss_user_entries.feed_id = ttrss_feeds.id AND";

			} else {
				$from_qpart = "${ext_tables_part}ttrss_entries LEFT JOIN ttrss_user_entries ON (ref_id = ttrss_entries.id)
						LEFT JOIN ttrss_feeds ON (feed_id = ttrss_feeds.id)";
				$feed_check_qpart = "";
			}

			if ($vfeed_query_part) $vfeed_query_part .= "favicon_avg_color,";

			$first_id_query_strategy_part = $query_strategy_part;

			if ($feed == -3)
				$first_id_query_strategy_part = "true";

			if (DB_TYPE == "pgsql") {
				$sanity_interval_qpart = "date_entered >= NOW() - INTERVAL '1 hour' AND";
				$yyiw_qpart = "to_char(date_entered, 'IYYY-IW') AS yyiw";

				$distinct_columns = str_replace("desc", "", strtolower($order_by));
				$distinct_qpart = "DISTINCT ON (id, $distinct_columns)";
			} else {
				$sanity_interval_qpart = "date_entered >= DATE_SUB(NOW(), INTERVAL 1 hour) AND";
				$yyiw_qpart = "date_format(date_entered, '%Y-%u') AS yyiw";
				$distinct_qpart = "DISTINCT"; //fallback
			}

			if (!$search && !$skip_first_id_check) {
				// if previous topmost article id changed that means our current pagination is no longer valid
				$query = "SELECT
							ttrss_entries.id,
							date_entered,
							$yyiw_qpart,
							guid,
							ttrss_entries.title,
							ttrss_feeds.title,
							updated,
							score,
							marked,
							published,
							last_marked,
							last_published,
							last_read
						FROM
							$from_qpart
						WHERE
						$feed_check_qpart
						ttrss_user_entries.owner_uid = ".$pdo->quote($owner_uid)." AND
						$search_query_part
						$start_ts_query_part
						$since_id_part
						$sanity_interval_qpart
						$first_id_query_strategy_part ORDER BY $order_by LIMIT 1";

				if (!empty($_REQUEST["debug"])) {
					print "\n*** FIRST ID QUERY ***\n$query\n";
				}

				$res = $pdo->query($query);

				if (!empty($res) && $row = $res->fetch()) {
					$first_id = (int)$row["id"];

					if ($offset > 0 && $first_id && $check_first_id && $first_id != $check_first_id) {
						return array(-1, $feed_title, $feed_site_url, $last_error, $last_updated, $search_words, $first_id, $vfeed_query_part != "", $query_error_override);
					}
				}
			}

			$query = "SELECT $distinct_qpart
						ttrss_entries.id AS id,
						date_entered,
						$yyiw_qpart,
						guid,
						ttrss_entries.title,
						updated,
						label_cache,
						tag_cache,
						always_display_enclosures,
						site_url,
						note,
						num_comments,
						comments,
						int_id,
						uuid,
						lang,
						hide_images,
						unread,feed_id,marked,published,link,last_read,
						last_marked, last_published,
						$vfeed_query_part
						$content_query_part
						author,score
					FROM
						$from_qpart
					WHERE
					$feed_check_qpart
					ttrss_user_entries.owner_uid = ".$pdo->quote($owner_uid)." AND
					$search_query_part
					$start_ts_query_part
					$view_query_part
					$since_id_part
					$query_strategy_part ORDER BY $order_by
					$limit_query_part $offset_query_part";

			//if ($_REQUEST["debug"]) print $query;

			if (!empty($_REQUEST["debug"])) {
				print "\n*** HEADLINES QUERY ***\n$query\n";
			}

			$res = $pdo->query($query);

		} else {
			// browsing by tag

			if (DB_TYPE == "pgsql") {
				$distinct_columns = str_replace("desc", "", strtolower($order_by));
				$distinct_qpart = "DISTINCT ON (id, $distinct_columns)";
			} else {
				$distinct_qpart = "DISTINCT"; //fallback
			}

			$query = "SELECT $distinct_qpart
							date_entered,
							guid,
							note,
							ttrss_entries.id as id,
							title,
							updated,
							unread,
							feed_id,
							marked,
							published,
							num_comments,
							comments,
							int_id,
							tag_cache,
							label_cache,
							link,
							lang,
							uuid,
							last_read,
							(SELECT hide_images FROM ttrss_feeds WHERE id = feed_id) AS hide_images,
							last_marked, last_published,
							$since_id_part
							$vfeed_query_part
							$content_query_part
							author, score
						FROM ttrss_entries, ttrss_user_entries, ttrss_tags
						WHERE
							ref_id = ttrss_entries.id AND
							ttrss_user_entries.owner_uid = ".$pdo->quote($owner_uid)." AND
							post_int_id = int_id AND
							tag_name = ".$pdo->quote($feed)." AND
							$view_query_part
							$search_query_part
							$start_ts_query_part
							$query_strategy_part ORDER BY $order_by
							$limit_query_part $offset_query_part";

			//if ($_REQUEST["debug"]) print $query;

			if (!empty($_REQUEST["debug"])) {
				print "\n*** TAGS QUERY ***\n$query\n";
			}

			$res = $pdo->query($query);
		}

		return array($res, $feed_title, $feed_site_url, $last_error, $last_updated, $search_words, $first_id, $vfeed_query_part != "", $query_error_override);

	}

	static function _get_parent_cats($cat, $owner_uid) {
		$rv = array();

		$pdo = Db::pdo();

		$sth = $pdo->prepare("SELECT parent_cat FROM ttrss_feed_categories
			WHERE id = ? AND parent_cat IS NOT NULL AND owner_uid = ?");
		$sth->execute([$cat, $owner_uid]);

		while ($line = $sth->fetch()) {
			array_push($rv, $line["parent_cat"]);
			$rv = array_merge($rv, self::_get_parent_cats($line["parent_cat"], $owner_uid));
		}

		return $rv;
	}

	static function _get_child_cats($cat, $owner_uid) {
		$rv = array();

		$pdo = Db::pdo();

		$sth = $pdo->prepare("SELECT id FROM ttrss_feed_categories
			WHERE parent_cat = ? AND owner_uid = ?");
		$sth->execute([$cat, $owner_uid]);

		while ($line = $sth->fetch()) {
			array_push($rv, $line["id"]);
			$rv = array_merge($rv, self::_get_child_cats($line["id"], $owner_uid));
		}

		return $rv;
	}

	static function _cat_of_feed($feed) {
		$pdo = Db::pdo();

	    $sth = $pdo->prepare("SELECT cat_id FROM ttrss_feeds
				WHERE id = ?");
	    $sth->execute([$feed]);

		if ($row = $sth->fetch()) {
			return $row["cat_id"];
		} else {
			return false;
		}

	}

    private function _color_of($name) {
        $colormap = [ "#1cd7d7","#d91111","#1212d7","#8e16e5","#7b7b7b",
            "#39f110","#0bbea6","#ec0e0e","#1534f2","#b9e416",
            "#479af2","#f36b14","#10c7e9","#1e8fe7","#e22727" ];

        $sum = 0;

        for ($i = 0; $i < strlen($name); $i++) {
            $sum += ord($name[$i]);
        }

        $sum %= count($colormap);

        return $colormap[$sum];
	}

	private static function _get_feeds_from_html($url, $content) {
		$url     = UrlHelper::validate($url);
		$baseUrl = substr($url, 0, strrpos($url, '/') + 1);

		$feedUrls = [];

		$doc = new DOMDocument();
		if (@$doc->loadHTML($content)) {
			$xpath = new DOMXPath($doc);
			$entries = $xpath->query('/html/head/link[@rel="alternate" and '.
				'(contains(@type,"rss") or contains(@type,"atom"))]|/html/head/link[@rel="feed"]');

			foreach ($entries as $entry) {
				if ($entry->hasAttribute('href')) {
					$title = $entry->getAttribute('title');
					if ($title == '') {
						$title = $entry->getAttribute('type');
					}
					$feedUrl = rewrite_relative_url(
						$baseUrl, $entry->getAttribute('href')
					);
					$feedUrls[$feedUrl] = $title;
				}
			}
		}
		return $feedUrls;
	}

	static function _is_html($content) {
		return preg_match("/<html|DOCTYPE html/i", substr($content, 0, 8192)) !== 0;
	}

	static function _add_cat($feed_cat, $parent_cat_id = false, $order_id = 0) {

		if (!$feed_cat) return false;

		$feed_cat = mb_substr($feed_cat, 0, 250);
		if (!$parent_cat_id) $parent_cat_id = null;

		$pdo = Db::pdo();
		$tr_in_progress = false;

		try {
			$pdo->beginTransaction();
		} catch (Exception $e) {
			$tr_in_progress = true;
		}

		$sth = $pdo->prepare("SELECT id FROM ttrss_feed_categories
				WHERE (parent_cat = :parent OR (:parent IS NULL AND parent_cat IS NULL))
				AND title = :title AND owner_uid = :uid");
		$sth->execute([':parent' => $parent_cat_id, ':title' => $feed_cat, ':uid' => $_SESSION['uid']]);

		if (!$sth->fetch()) {

			$sth = $pdo->prepare("INSERT INTO ttrss_feed_categories (owner_uid,title,parent_cat,order_id)
					VALUES (?, ?, ?, ?)");
			$sth->execute([$_SESSION['uid'], $feed_cat, $parent_cat_id, (int)$order_id]);

			if (!$tr_in_progress) $pdo->commit();

			return true;
		}

		$pdo->commit();

		return false;
	}

	static function _get_access_key($feed_id, $is_cat, $owner_uid = false) {

		if (!$owner_uid) $owner_uid = $_SESSION["uid"];

		$is_cat = bool_to_sql_bool($is_cat);

		$pdo = Db::pdo();

		$sth = $pdo->prepare("SELECT access_key FROM ttrss_access_keys
				WHERE feed_id = ? AND is_cat = ?
				AND owner_uid = ?");
		$sth->execute([$feed_id, $is_cat, $owner_uid]);

		if ($row = $sth->fetch()) {
			return $row["access_key"];
		} else {
			$key = uniqid_short();

			$sth = $pdo->prepare("INSERT INTO ttrss_access_keys
					(access_key, feed_id, is_cat, owner_uid)
					VALUES (?, ?, ?, ?)");

			$sth->execute([$key, $feed_id, $is_cat, $owner_uid]);

			return $key;
		}
	}

	/**
	 * Purge a feed old posts.
	 *
	 * @param mixed $feed_id The id of the purged feed.
	 * @param mixed $purge_interval Olderness of purged posts.
	 * @access public
	 * @return mixed
	 */
	static function _purge($feed_id, $purge_interval) {

		if (!$purge_interval) $purge_interval = self::_get_purge_interval($feed_id);

		$pdo = Db::pdo();

		$owner_uid = false;
		$rows_deleted = 0;

		$sth = $pdo->prepare("SELECT owner_uid FROM ttrss_feeds WHERE id = ?");
		$sth->execute([$feed_id]);

		if ($row = $sth->fetch()) {
			$owner_uid = $row["owner_uid"];

			if (FORCE_ARTICLE_PURGE != 0) {
				Debug::log("purge_feed: FORCE_ARTICLE_PURGE is set, overriding interval to " . FORCE_ARTICLE_PURGE, Debug::$LOG_VERBOSE);
				$purge_unread = true;
				$purge_interval = FORCE_ARTICLE_PURGE;
			} else {
				$purge_unread = get_pref("PURGE_UNREAD_ARTICLES", $owner_uid, false);
			}

			$purge_interval = (int) $purge_interval;

			Debug::log("purge_feed: interval $purge_interval days for feed $feed_id, owner: $owner_uid, purge unread: $purge_unread", Debug::$LOG_VERBOSE);

			if ($purge_interval <= 0) {
				Debug::log("purge_feed: purging disabled for this feed, nothing to do.", Debug::$LOG_VERBOSE);
				return;
			}

			if (!$purge_unread)
				$query_limit = " unread = false AND ";
			else
				$query_limit = "";

			if (DB_TYPE == "pgsql") {
				$sth = $pdo->prepare("DELETE FROM ttrss_user_entries
					USING ttrss_entries
					WHERE ttrss_entries.id = ref_id AND
					marked = false AND
					feed_id = ? AND
					$query_limit
					ttrss_entries.date_updated < NOW() - INTERVAL '$purge_interval days'");
				$sth->execute([$feed_id]);

			} else {
				$sth  = $pdo->prepare("DELETE FROM ttrss_user_entries
					USING ttrss_user_entries, ttrss_entries
					WHERE ttrss_entries.id = ref_id AND
					marked = false AND
					feed_id = ? AND
					$query_limit
					ttrss_entries.date_updated < DATE_SUB(NOW(), INTERVAL $purge_interval DAY)");
				$sth->execute([$feed_id]);

			}

			$rows_deleted = $sth->rowCount();

			Debug::log("purge_feed: deleted $rows_deleted articles.", Debug::$LOG_VERBOSE);

		} else {
			Debug::log("purge_feed: owner of $feed_id not found", Debug::$LOG_VERBOSE);
		}

		return $rows_deleted;
	}

	private static function _get_purge_interval($feed_id) {

		$pdo = Db::pdo();

		$sth = $pdo->prepare("SELECT purge_interval, owner_uid FROM ttrss_feeds
			WHERE id = ?");
		$sth->execute([$feed_id]);

		if ($row = $sth->fetch()) {
			$purge_interval = $row["purge_interval"];
			$owner_uid = $row["owner_uid"];

			if ($purge_interval == 0)
				$purge_interval = get_pref('PURGE_OLD_DAYS', $owner_uid, false);

			return $purge_interval;
		} else {
			return -1;
		}
	}

	private static function _search_to_sql($search, $search_language, $owner_uid) {

		$keywords = str_getcsv(trim($search), " ");
		$query_keywords = array();
		$search_words = array();
		$search_query_leftover = array();

		$pdo = Db::pdo();

		if ($search_language)
			$search_language = $pdo->quote(mb_strtolower($search_language));
		else
			$search_language = $pdo->quote(mb_strtolower(get_pref('DEFAULT_SEARCH_LANGUAGE', $owner_uid)));

		foreach ($keywords as $k) {
			if (strpos($k, "-") === 0) {
				$k = substr($k, 1);
				$not = "NOT";
			} else {
				$not = "";
			}

			$commandpair = explode(":", mb_strtolower($k), 2);

			switch ($commandpair[0]) {
				case "title":
					if ($commandpair[1]) {
						array_push($query_keywords, "($not (LOWER(ttrss_entries.title) LIKE ".
							$pdo->quote('%' . mb_strtolower($commandpair[1]) . '%') ."))");
					} else {
						array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER('%$k%')
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						array_push($search_words, $k);
					}
					break;
				case "author":
					if ($commandpair[1]) {
						array_push($query_keywords, "($not (LOWER(author) LIKE ".
							$pdo->quote('%' . mb_strtolower($commandpair[1]) . '%')."))");
					} else {
						array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER('%$k%')
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						array_push($search_words, $k);
					}
					break;
				case "note":
					if ($commandpair[1]) {
						if ($commandpair[1] == "true")
							array_push($query_keywords, "($not (note IS NOT NULL AND note != ''))");
						else if ($commandpair[1] == "false")
							array_push($query_keywords, "($not (note IS NULL OR note = ''))");
						else
							array_push($query_keywords, "($not (LOWER(note) LIKE ".
								$pdo->quote('%' . mb_strtolower($commandpair[1]) . '%')."))");
					} else {
						array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER(".$pdo->quote("%$k%").")
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						if (!$not) array_push($search_words, $k);
					}
					break;
				case "star":

					if ($commandpair[1]) {
						if ($commandpair[1] == "true")
							array_push($query_keywords, "($not (marked = true))");
						else
							array_push($query_keywords, "($not (marked = false))");
					} else {
						array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER(".$pdo->quote("%$k%").")
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						if (!$not) array_push($search_words, $k);
					}
					break;
				case "pub":
					if ($commandpair[1]) {
						if ($commandpair[1] == "true")
							array_push($query_keywords, "($not (published = true))");
						else
							array_push($query_keywords, "($not (published = false))");

					} else {
						array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER('%$k%')
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						if (!$not) array_push($search_words, $k);
					}
					break;
				case "label":
					if ($commandpair[1]) {
						$label_id = Labels::find_id($commandpair[1], $_SESSION["uid"]);

						if ($label_id) {
							array_push($query_keywords, "($not
								(ttrss_entries.id IN (
									SELECT article_id FROM ttrss_user_labels2 WHERE
										label_id = ".$pdo->quote($label_id).")))");
						} else {
							array_push($query_keywords, "(false)");
						}
					} else {
						array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER(".$pdo->quote("%$k%").")
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						if (!$not) array_push($search_words, $k);
					}
					break;
				case "unread":
					if ($commandpair[1]) {
						if ($commandpair[1] == "true")
							array_push($query_keywords, "($not (unread = true))");
						else
							array_push($query_keywords, "($not (unread = false))");

					} else {
						array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER(".$pdo->quote("%$k%").")
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						if (!$not) array_push($search_words, $k);
					}
					break;
				default:
					if (strpos($k, "@") === 0) {

						$user_tz_string = get_pref('USER_TIMEZONE', $_SESSION['uid']);
						$orig_ts = strtotime(substr($k, 1));
						$k = date("Y-m-d", TimeHelper::convert_timestamp($orig_ts, $user_tz_string, 'UTC'));

						//$k = date("Y-m-d", strtotime(substr($k, 1)));

						array_push($query_keywords, "(".SUBSTRING_FOR_DATE."(updated,1,LENGTH('$k')) $not = '$k')");
					} else {

						if (DB_TYPE == "pgsql") {
							$k = mb_strtolower($k);
							array_push($search_query_leftover, $not ? "!$k" : $k);
						} else {
							array_push($query_keywords, "(UPPER(ttrss_entries.title) $not LIKE UPPER(".$pdo->quote("%$k%").")
								OR UPPER(ttrss_entries.content) $not LIKE UPPER(".$pdo->quote("%$k%")."))");
						}

						if (!$not) array_push($search_words, $k);
					}
			}
		}

		if (count($search_query_leftover) > 0) {

			if (DB_TYPE == "pgsql") {

				// if there's no joiners consider this a "simple" search and
				// concatenate everything with &, otherwise don't try to mess with tsquery syntax
				if (preg_match("/[&|]/", implode(" " , $search_query_leftover))) {
					$tsquery = $pdo->quote(implode(" ", $search_query_leftover));
				} else {
					$tsquery = $pdo->quote(implode(" & ", $search_query_leftover));
				}

				array_push($query_keywords,
					"(tsvector_combined @@ to_tsquery($search_language, $tsquery))");
			}

		}

		if (count($query_keywords) > 0)
			$search_query_part = implode("AND", $query_keywords);
		else
			$search_query_part = "false";

		return array($search_query_part, $search_words);
	}

	static function _order_to_override_query($order) {
		$query = "";
		$skip_first_id = false;

		PluginHost::getInstance()->chain_hooks_callback(PluginHost::HOOK_HEADLINES_CUSTOM_SORT_OVERRIDE,
			function ($result) use (&$query, &$skip_first_id) {
				list ($query, $skip_first_id) = $result;
			},
			$order);

		if ($query)	return [$query, $skip_first_id];

		switch ($order) {
			case "title":
				$query = "ttrss_entries.title, date_entered, updated";
				break;
			case "date_reverse":
				$query = "updated";
				$skip_first_id = true;
				break;
			case "feed_dates":
				$query = "updated DESC";
				break;
		}

		return [$query, $skip_first_id];
	}

	private function _mark_timestamp($label) {

		if (empty($_REQUEST['timestamps']))
			return;

		if (!$this->viewfeed_timestamp) $this->viewfeed_timestamp = hrtime(true);
		if (!$this->viewfeed_timestamp_last) $this->viewfeed_timestamp_last = hrtime(true);

		$timestamp = hrtime(true);

		printf("[%4d ms, %4d abs] %s\n",
			($timestamp - $this->viewfeed_timestamp_last) / 1e6,
			($timestamp - $this->viewfeed_timestamp) / 1e6,
			$label);

		$this->viewfeed_timestamp_last = $timestamp;
	}

}